TrES-1 transit of September 4th, 2004

Following my  successful TrES-1 transit observation of Sep 1st, 2004, I had the opportunity to again observe a transit of TrES-1, just one orbital period after its previous passage in front of its host star. 

Sep 4th, 2004 was a clear night over CBA Belgium Observatory, although the sky was slightly hazy. Around 20h38m UT, I pointed one of the CBA Belgium Observatory telescopes at TrES-1's host star and started an unfiltered time-series photometry session. Several hours later, around 01h23m UT (Sep 5, 2004) the session was concluded because of fog making further observations impossible (fortunately, this was past egress). 

The resulting transit lightcurve is shown below. I used ensemble photometry with a set of 7 comparison stars to reduce the observations. Each dot or bin in the light curve is the average differential magnitude of 3 subsequent CCD images. 

A rough inspection of the light curve seems to confirm my initial findings : again, ingress and egress happened later (about 10 min) than predicted by the TrES-1 ephemeris on


TrES-1 transit of Sep 4, 2004. Light curve based on photometry with 7 comparison stars.
Each dot or bin is the average differential mag of 3 subsequent  CCD images.
(c) Tonny Vanmunster, CBA Belgium Observatory

Other amateur astronomers monitored the TrES-1 transit of Sep 4th, 2004 as well. Watch their results here :

Ondrej Pejcha observing from Brno, Czech Republic with a 0.40-m telescope and unfiltered ST-7

Pertti Pääkkönen and Tommi Itkonen observing from Jakokoski Observatory, Finland with a 0.50-m telescope and ST1001E with V-filter





Copyright © 2004 - Tonny Vanmunster.